Arrangement in a radio system

Abstract

The present invention relates to an arrangement for connecting antennas to ports of a transceiver unit in a base station. By using two circulators and a four port sputter a more flexible small base station is attained. The arrangement provides, at a low extra cost, the capability of adding an auxiliary transceiver unit to the base station.

1. A base station arrangement for connecting a first antenna and a second antenna to a first port, intended for transmitting and receiving radio frequency signals, and a second port, intended for receiving radio frequency signals, of a transceiver unit, comprising:
 a first circulator unit, a second circulator unit and a four port splitter unit,  
 said first circulator unit having a first port connected to the first port of the transceiver unit, a second port connected to the first antenna and a third port connected to a first port of the splitter unit; said first circulator unit being designed so that signals inputted at its first port are outputted at its second port only, signals are inputted at its second port are outputted at its third port only, and signals inputted at its third port are outputted at its first port only;  
 said second circulator having a first port connected to the second antenna and a second port connected a to second port of the splitter unit and a third port; said second circulator being designed so that signals inputted at its first port are outputted at its second port only, signals inputted at its second port are outputted at its third port only, and signals inputted at its third port are outputted at its first port only;  
 said splitter unit having a third port connected to said second port of the transceiver unit;  
 said splitter unit being designed so that signals inputted at its first port are outputted at its second and third ports, and that signals inputted at its second port are outputted at its first and fourth ports.  
 
   
   
     2. An arrangement claimed in  claim 1 , futher comprising:
 a first matched resistor element connected to the fourth port of the splitter unit and a second matched resistor element connected to the third port of the second circulator.  
 
   
   
     3. An arrangement claimed in  claim 1 , further comprising:
 an auxiliary transceiver unit having a first port, intended for transmitting and receiving radio frequency signals, connected to the third port of the second circulator, and a second port intended for receiving radio frequency signals, connected to the fourth port of the splitter unit.  
 
   
   
     4. An arrangement claimed in  claim 3 , wherein the splitter unit is designed to split signals incoming at its second port unevenly in a degree compensating for the attenuation between two circular ports. 
   
   
     5. An arrangement claimed in  claim 3 , wherein one transceiver unit is adapted for voice traffic and the other for packet data traffic. 
   
   
     6. An arrangement claimed in  claim 3 , wherein the splitter unit is a microstrip branchline splitter.